Treatment system for preventing ammonium sulfate blockage in caprolactam production
By adding benzene before the amide oil storage tank during the caprolactam production process, the problem of ammonium sulfate blocking the pipeline is solved, and the amount of benzene added and equipment size of benzene extracted is reduced, energy consumption is reduced, and production efficiency is improved.
Patent Information
- Application Number
- CN202421495494.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-27
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-06-27
AI Technical Summary
During the production process of caprolactam, ammonium sulfate precipitates after cooling, resulting in pipeline blockage and deposition. Although the existing water addition method solves the blockage problem, it increases the amount of benzene extraction and equipment size in subsequent processes, resulting in an increase in energy consumption and an increase in wastewater.
After caprolactam crystallizes, benzene is added before entering the amide oil storage tank, and the benzene is dissolved with water to dissolve ammonium sulfate to prevent it from precipitation and blocking the pipeline.
It effectively prevents ammonium sulfate from clogging the pipeline, and at the same time reduces the amount of benzene extracted, reduces the equipment size and energy consumption, and improves production efficiency.
Smart Images
Figure CN222930334U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a caprolactam production equipment, in particular to a treatment system for preventing ammonium sulfate blockage in caprolactam production. Background Art
[0002] Caprolactam is an important raw material for chemical fibers and engineering plastics. At present, the main production process for caprolactam is the cyclohexanone-hydroxylamine route based on the Beckmann rearrangement of cyclohexanone oxime, that is, benzene is hydrogenated to cyclohexane, cyclohexane is oxidized to cyclohexanone, then it reacts with hydroxylamine to form cyclohexanone oxime, and then caprolactam is obtained through Beckmann rearrangement. After the Beckmann rearrangement reaction, ammonia is added to neutralize the fuming sulfuric acid in the rearrangement solution. Water is evaporated by the heat of the neutralization reaction in the crystallizer. The neutralization product ammonium sulfate forms a crystal slurry in the crystallizer. The caprolactam solution is separated from the ammonium sulfate crystal slurry. The amide oil (caprolactam aqueous solution is called amide oil) containing a large amount of ammonium sulfate solution is pumped out at the interface of the crystallizer by the P2 pump. The conventional method to solve the blockage: after phase separation by a settler (phase separator), it enters the amide oil storage tank for buffering and static separation, and is pumped into the extraction tower by the P4 pump. After benzene extraction, it enters the subsequent process. The ammonium sulfate mother liquor at the lower part of the amide oil storage tank returns to the inlet of the circulating pump P1 of the crystallizer through the P3 pump. Generally, the evaporation temperature of the crystallizer is 56 - 58 °C, the caprolactam concentration in the amide oil is 75% - 76%. The extracted amide oil contains a saturated ammonium sulfate solution. When the temperature drops, ammonium sulfate will precipitate and block the pipeline, and ammonium sulfate will deposit at the bottom of the amide oil storage tank. All these require operators to clean regularly, which brings great inconvenience to the operation. At present, to solve the problem of ammonium sulfate precipitation and blockage of the pipeline during cooling, water is mainly added to the pipeline between the P2 pump and the crystallizer (see Figure 1 ), which dissolves ammonium sulfate and avoids pipeline blockage. At the same time, the caprolactam concentration in the extracted amide oil is also reduced to 72.5%. Although adding water solves the problem of ammonium sulfate blockage of the pipeline when the amide oil is pumped out at present, since the subsequent amide oil needs to be benzene-extracted in the benzene extraction tower, adding water leads to an increase in the amount of benzene added during benzene extraction. Basically, 0.034 tons of water needs to be added to 1 ton of amide oil, and 0.37 tons more benzene is needed for benzene extraction, resulting in an increase in the equipment size of the benzene extraction tower, an increase in the energy consumption of benzene removal in the later stage, and an increase in wastewater. Summary of the Utility Model
[0003] The utility model provides a treatment system for preventing ammonium sulfate blockage in caprolactam production, which solves the problem of pipeline blockage when the amide oil is pumped out and at the same time reduces the amount of benzene added and the equipment size in benzene extraction.
[0004] The technical solution to solve the above problems is a treatment system for preventing ammonium sulfate blockage in caprolactam production. After caprolactam is crystallized, it is transported to the amide oil storage tank for separation. The method includes adding benzene before caprolactam enters the amide oil storage tank after crystallization.
[0005] Preferably, the mass ratio of benzene added to the mass of amide oil is 1:0.5 - 100, and the amount of benzene added in the later benzene extraction is reduced by at least 1:10.
[0006] A treatment system for preventing ammonium sulfate blockage in caprolactam production. The caprolactam production system includes: a clarifier, an amide oil storage tank, and a benzene extraction tower. The crystallizer is connected to the upper part of the amide oil storage tank through a second delivery pump. The amide oil storage tank is connected to the benzene extraction tower through a fourth delivery pump. The lower part of the amide oil storage tank is connected to the clarifier through a third delivery pump. The treatment system includes a first benzene injection pipe provided between the clarifier and the second delivery pump and / or a second benzene injection pipe provided between the second delivery pump and the amide oil storage tank. Benzene enters the second delivery pump through the first benzene injection pipe and / or benzene enters the amide oil storage tank through the second injection pipe.
[0007] Preferably, a first control valve is provided on the first benzene injection pipe.
[0008] Preferably, the second benzene injection pipe is inserted into the second control valve.
[0009] Preferably, the treatment system further includes a controller. The first control valve is an electrically controlled valve, and the controller is electrically connected to the first control valve.
[0010] Preferably, the treatment system further includes a controller. The second control valve is an electrically controlled valve, and the controller is electrically connected to the second control valve.
[0011] The advantages of the present utility model are as follows: 1) Benzene is miscible with caprolactam and water. After adding benzene, the water in the amide oil dissolves ammonium sulfate, solving the problem of pipeline blockage when the amide oil is extracted.
[0012] 2) After adopting this solution, at least 0.1 ton less benzene is added during benzene extraction in the benzene extraction tower. The size of the extraction equipment in the benzene extraction tower is reduced by 2 - 5%, reducing equipment investment. The energy consumption for benzene removal in the later stage is correspondingly reduced by more than 1%. It has great economic advantages for industrial caprolactam projects. Description of the Drawings
[0013] Figure 1 It is a diagram of the prior art.
[0014] Figure 2 It is a schematic structural diagram of the present utility model.
[0015] Figure 3 It is a preferred schematic structural diagram of the present utility model.
[0016] As shown in the figure: separator 1, amide oil storage tank 2, benzene extraction tower 3, second transfer pump 4, fourth transfer pump 5, third transfer pump 6, first benzene injection pipe 7, second benzene injection pipe 8, first control valve 9, second control valve 10, controller 11. Detailed implementation
[0017] A method for preventing ammonium sulfate blockage in caprolactam production. After passing through the separator, caprolactam is transported to the amide oil storage tank for separation. The method includes adding benzene before caprolactam enters the amide oil storage tank after passing through the separator. The mass ratio of the added benzene to the amide oil is 1:0.5 - 100.
[0018] As Figure 2 As shown, a treatment system for preventing ammonium sulfate blockage in caprolactam production. The caprolactam production system includes a separator 1, an amide oil storage tank 2, and a benzene extraction tower 3. The separator 1 is connected to the upper part of the amide oil storage tank 2 through the second transfer pump 4. The amide oil storage tank 2 is connected to the benzene extraction tower 3 through the fourth transfer pump 5. The lower part of the amide oil storage tank 2 is connected to the separator 1 through the third transfer pump 6. The treatment system includes a first benzene injection pipe 7 between the separator 1 and the second transfer pump 4 and / or a second benzene injection pipe 8 between the second transfer pump 4 and the amide oil storage tank 2. Benzene enters the second transfer pump 4 through the first benzene injection pipe 7 and / or benzene enters the amide oil storage tank 2 through the second injection pipe 8.
[0019] Working principle: Utilizing the physical properties that benzene and water are immiscible, both benzene and water can be miscible with caprolactam, benzene does not dissolve ammonium sulfate, and caprolactam does not dissolve ammonium sulfate. By adding benzene, the dissolved amount of water in caprolactam is reduced, making the ammonium sulfate in the aqueous phase change from a saturated state to an unsaturated state, thus preventing the phenomenon of ammonium sulfate precipitation and pipeline blockage.
[0020] The amide oil (caprolactam aqueous solution is called amide oil) pumped out from the separator by the second transfer pump 4 is cached and statically separated in the amide oil storage tank 2, and then pumped into the extraction tower 3 by the fourth transfer pump 5. After adding benzene at the output of the separator and entering the lower part of the amide oil storage tank 2, the ammonium sulfate mother liquor returns to the separator 1 through the third transfer pump 6; benzene enters the second transfer pump 4 through the first benzene injection pipe 7 and finally enters the amide oil storage tank 2, and / or enters the amide oil storage tank 2 through the second benzene injection pipe 8. The mass ratio of benzene added to 1 ton of amide oil is 0.01 - 1 ton. After adding benzene, the amide oil enters the amide oil storage tank 2. After being cached in the amide oil storage tank 2, the amide oil is pumped into the benzene extraction tower 3 by the fourth transfer pump 5. The mother liquor containing sodium sulfate enters the inlet of the circulation pump through the third transfer pump 6 and enters the separator (phase separator) 1, or can also be sent to the ammonium sulfate crystallizer. There is no blockage of ammonium sulfate in the entire pipeline.
[0021] Preferably, as Figure 3As shown, a first control valve 9 is provided on the first benzene injection pipe 7.
[0022] Preferably, the second benzene injection pipe 8 is inserted into the second control valve 10. The processing system further includes a controller 11. The first control valve 9 is an electrically controlled valve, and the controller 11 is electrically connected to the first control valve 9.
[0023] Preferably, the processing system further includes a controller 11. The second control valve 10 is an electrically controlled valve, and the controller 11 is electrically connected to the second control valve 10.
[0024] During operation, the controller 11 controls the opening degrees of the first control valve 9 and the second control valve 10 according to the set parameters, so as to control the benzene injection amount. The set parameters of the controller 11 are related to the working power of the third delivery pump 3.
Claims
1. A treatment system for preventing ammonium sulfate from clogging in caprolactam production, the caprolactam production system comprising a separator and an amide oil storage tank, the separator is connected to the upper part of the amide oil storage tank through a second delivery pump, the lower part of the amide oil storage tank is connected to a benzol extraction tower through a fourth delivery pump, and the lower part of the amide oil storage tank is connected to the separator through a third delivery pump, characterized in that: The treatment system includes a first benzene injection pipe between the filter and the second delivery pump and / or a second benzene injection pipe between the second delivery pump and the amide oil storage tank, and benzene enters the second delivery pump through the first benzene injection pipe and / or benzene enters the amide oil storage tank through the second benzene injection pipe.
2. A treatment system for preventing ammonium sulfate from clogging in caprolactam production according to claim 1, characterized in that: The first benzene injection pipe is provided with a first control valve.
3. A treatment system for preventing ammonium sulfate from clogging in caprolactam production according to claim 1, characterized in that: The second benzene injection pipe is inserted into the second control valve.
4. A treatment system for preventing ammonium sulfate from clogging in caprolactam production according to claim 2, characterized in that: The processing system further includes a controller, the first control valve is an electrically controlled valve, and the controller is electrically connected to the first control valve.
5. A treatment system for preventing ammonium sulfate from clogging in caprolactam production according to claim 3, characterized in that: The processing system further includes a controller, the second control valve is an electrically controlled valve, and the controller is electrically connected to the second control valve.